Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - DCR Calculation
Thread: DCR Calculation
View Single Post
  #19 (permalink)  
Old 01-17-2013, 03:23 PM
cobalt327's Avatar
cobalt327 cobalt327 is offline
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 60
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by bygddy View Post
And yet up top......

Recently had a similar error by Summit. A guy posted a Pontiac (IIRC) piston p/n he was going to order that ended with -060, but he thought the piston was a standard size- like the info on Summit's site said it was. Obviously a mistake, but to someone new to it all, it went right over his head and would have cost him a lot of time and trouble had it not been caught.

I don't get why suddenly some have seemingly forgotten the rules of thumb that go along w/CR and octane. C'mon guys! Ain't no free lunch, don't matter how much cam you throw at it.

I do believe DCR has its place. But when you go way outside the box, it will break down.

As far as errors caused by the advertised vs. actual seat to seat timing, etc., if you run the numbers both ways, you'll see there's not that much difference in the results. The only way it would matter is if the combo was right at the limit, and that's risky no matter how you look at it.

Lastly, IMHO losing a couple tenths of a point of CR to stay safe is MUCH preferable than to run less than best timing. A couple degrees of timing can cost 50-plus HP in the blink of an eye. .5:1 CR has been estimated to be worth ~2%, or 10 HP on a 500 HP build. I know which one I would choose.

Last edited by cobalt327; 01-17-2013 at 03:34 PM.
Reply With Quote
The Following User Says Thank You to cobalt327 For This Useful Post:
1Gary (01-18-2013)